Northstar Engines and System Technical Discussion Discussion, Northstar exhaust in Cadillac Engine Discussion; HAVING A DEBATE ABOUT TRUE DUAL EXHAUST ( header to pipe straight back) and if the N* 4.6 WOULD HAVE ...

Northstar exhaust

HAVING A DEBATE ABOUT TRUE DUAL EXHAUST ( header to pipe straight back) and if the N* 4.6 WOULD HAVE BACK PRESSURE ISSUES AND CAUSE COMPUTER CONFLICTS.
WITH ONE PIPE PER HEADER. HOW TOUCHY ARE THESE CARS.

Re: Northstar exhaust

imo it can be done. i just replaced the head gaskets on my 98 sts and while i had it apart i looked for a dual exhaust solution.. it looks tight but i think you could do it... furthermore the front bank pipe runs into the downpipe at about an 85 degree angle which is clearly not great for flow and adds turbulence to the flow of the rear bank exhaust. i think if you found a dual inlet/outlet cat converter it would be ok... i will attempt it at some point... the major problem i see would be actually welding the new downpipe off the front bank crossover(at the correct angle)

Re: Northstar exhaust

There is a member on the Aurora club with a Shelby engine in his Aurora that has true dual exhaust, I will see if I can find a thread about it. He could tell you more about any back pressure issues if any exist. I think one of the biggest killers is the exhaust manifolds, they have like a dual wall in them that takes up a lot of space on the inside of the exhaust, I have been trying to figure out a way to remove it, I have been considering cutting the manifold open, removing the guts, and then welding it back together. I have already cleaned my y flex pipe, I am waiting to install it with my 4.6 into my Aurora, I also have a hallowed catalytic convertor, it throws a code, but that should be fixed with my Madtuner tuned pcm.

Re: Northstar exhaust

Here's Joe Tahoe's CORSA install as of last year. Not much room to spread out. Even worse up toward the resonator and Y/flex coupling. When I did my CORSA the car was up on a 4-point at the local AMJ Automotive - we looked long and hard at the room to work with, the little (279 c.i) Northstar engine, and the pipe ID's. The extra weight, cat(s), sensor(s), and labor was not worth the minimal gains in a FWD car with a non-programable PCM (1998-on). We're also screwed by the "crossunder" pipe arrangement coupled with the low under-engine ground clearance.

Notice how Joe's Y-pipe area is off-center in the tunnel - that can be cured by using small screw band hose clamps on the muffler hanger rods: The front flex coupling allows you to move the entire system back and forth - center it, use a hose clamp against each side of the muffler hanger cookies, and BINGO ! - the exhaust system will not walk side-to-side.